A safety pin is a variation of the regular pin which includes a simple spring mechanism and a clasp. The clasp forms a closed loop to properly fasten the pin to whatever it is applied to and covers the end of the pin to protect the user from the sharp point.
A safety pin.
A ribbon and badge attached to a school cap with safety pins
Hunt's 1849 patent on the safety pin, U.S. patent #6,281
Silver safety pins
A pin is a device, typically pointed, used for fastening objects or fabrics together. Pins can have the following sorts of body:a shaft of a rigid inflexible material meant to be inserted in a slot, groove, or hole
a shaft connected to a head and ending in a sharp tip meant to pierce one or more pieces of soft materials like cloth or paper
a single strip of a rigid but flexible material whose length has been folded into parallel prongs in such fashion that the middle length of each curves towards the other so that, when anything is inserted between them, they act as a clamp
two strips of a rigid material bound together by a spring at one end so that, when the spring held open, one can insert some material between the prongs at the other end that, the spring allowed to close, then clamp the inserted material.
A sewing pin
A safety pin
Push-pins in a cork board
Bone and metal pins used to fasten clothing in the Bronze Age